Correlations and structure factor of bicontinuous microemulsions

The correlation functions and structure factor of microemulsions are calculated from a statistical thermodynamic approach which has been previously used to obtain the equilibrium phase diagrams. The structure factor, S (q ), has a peak at a wavevector qmax ~ π/ξ where ξ is the domain size of the oil and water regions. The physical origin of this peak are the correlations induced by the presence of the curvature energy of the surfactant film ; the renormalization of the bending modulus by thermal fluctuations plays an important role in stabilizing these fluctuations. Real space representations of these correlations show that there is significant strength in S(q) from several different wavevectors.